The first example uses Requery to refresh a recordset after the underlying data is changed. The second example uses Requery to refresh a recordset after an underlying query parameter is changed.
See How to Build the DAO Method Samples.
On the MSDN Library discIf you have installed the DAO SDK, see Samples\dbdaoInstallDirectory\DAOSDK\SAMPLES\RequeryX1.cpp and RequeryX2.cpp.